Cover cropping is big trend in Atlantic Canada’s potato acres

At the start of Living Lab –Atlantic in 2019, fewer than 24 per cent of acres in potato production were planted with cover crops in the fall before planting potatoes. By the end of 2022 that number doubled to nearly 50 per cent and is expected to grow through peer-to-peer knowledge transfer led by Living Lab – Atlantic participants and funding available to farmers through the On-Farm Climate Action Fund.

Dr. Judith Nyiraneza, an Agriculture and Agri-Food Canada research scientist, coleads the cover crop research that has spanned four years. While involving several farmers and other researchers, she also works with PEI Potato Board research and agronomy specialist Ryan Barrett and Brandon MacPhail from MacSull Farms Ltd.

Dr. Nyiraneza, Ryan, Brandon and other participating farmers recently completed Living Lab –Atlantic research activities that set out to “uncover” the ideal use of cover crops within potato cropping systems and how they can be planted several times throughout the year, with varying benefits to farmers and their soil.

At AAFC’s Harrington

Research Farm, Dr. Nyiraneza studied full-season cover crops that are planted over an entire growing season then plowed into the soil in the fall, prior to planting a potato crop the following spring. She tested a broad range of crops including grasses, legumes, and a mixture of legumes and grasses and found that pearl millet returns the highest carbon input into the soil.

Pearl millet and sorghum sudangrass were associated with lower risk of soil nitrate leaching and higher total potato yield.

In another study, Dr. Nyiraneza evaluated winter cover crops planted in early to mid-September prior to planting potatoes the following spring. She found that winter cover crops, such as winter rye or winter wheat, reduced both soil erosion and nitrate leaching proving to be beneficial to the environment.

Not only does winter rye and wheat recover quickly in early spring, they can provide additional protection during snow melt when risk of soil erosion is very high. Plus, farmers can also harvest it as a second cash crop.

If harvested, winter wheat yield ranged from 4.5 to 7.6 tons per hectare and winter rye ranged from 3.2 to 5.1 tons per hectare.

Ryan Barrett has spent the last four years working with farmers, such as Brandon MacPhail, across the island to study fallseeded cover crops. These cover crops are planted after harvest of a cash crop or after tillage to prepare for next year’s crop. They include common grain crops such as barley or oats, as well as newer crops to PEI such as daikon radish. MacPhail and other participating farmers contributed to cover crop testing and research by supplying the land, seed, equipment, time, and staff to undertake the crop management practice.

Along with researchers, they determined which crops to plant as cover, in which fields, and for which production crops to follow. Barrett used splash pans in cover crop fields to measure the soil’s vulnerability to be moved through erosion. Splash pans were introduced by Dr. Nyiraneza and tested in previous studies. They are simple ways to measure the soil particles splashed by raindrops. Nitrates in the soil were measured at different times throughout the fall, and soil health tests were performed before and after cover crops were grown. The data that Barrett and participating farmers unearthed was a huge endorsement for cover crops.